Editing Variable-Rate Multimode Wideband

{{Infobox file format
|name         = Variable-Rate Multimode Wideband (VMR-WB)
|icon         =
|logo         = 
|caption      = 
|extension    = 
|mime         = audio/VMR-WB
|type code    = 
|uniform type =
|magic        = 
|owner        = [[3GPP2]]
|released     = <!-- {{Start date|YYYY|mm|dd|df=yes}} -->
|latest release version = 
|latest release date    = <!-- {{Start date and age|YYYY|mm|dd|df=yes/no}} -->
|type         = [[Lossy compression|Lossy]] [[Audio file format|audio]]
|containerfor =
|containedby  = [[3GP|3G2]], [[Real-time Transport Protocol|RTP]]
|extendedfrom = [[AMR-WB]]/G.722.2
|extendedto   =
|standard     = 
|url          = [http://www.3gpp2.org/public_html/specs/tsgc.cfm 3GPP2 standards]
}}
'''Variable-Rate Multimode Wideband''' ('''VMR-WB''') is a source-controlled variable-rate multimode [[codec]] designed for robust encoding/decoding of wideband/narrowband speech. The operation of VMR-WB is controlled by speech signal characteristics (i.e., source-controlled) and by traffic condition of the network (i.e., network-controlled mode switching). Depending on the traffic conditions and the desired quality of service ([[Quality of service|QoS]]), one of the 4 operational modes is used. All operating modes of the existing VMR-WB standard are fully compliant with [[cdma2000]] rate-set II. VMR-WB modes 0, 1, and 2 are cdma2000 native modes with mode 0 providing the highest quality and mode 2 the lowest ADR. VMR-WB mode 3 is the [[AMR-WB]] interoperable mode operating at an ADR slightly higher than mode 0 and providing a quality equal or better than that of AMR-WB at 12.65&nbsp;kbit/s when in an interoperable interconnection with AMR-WB at 12.65&nbsp;kbit/s.

Now also a cdma2000 rate-set I compliant mode is implemented to the coder as mode 4. The average bitrate of the mode is 6.1&nbsp;kbit/s (maximum is 8.55&nbsp;kbit/s). Source coding bitrates are: Rate-Set I - 8.55, 4.0, 2.0, 0.8&nbsp;kbit/s, Rate-Set II - 13.3, 6.2, 2.7, 1.0&nbsp;kbit/s. VMR-WB uses 16&nbsp;kHz sampling frequency.<ref>{{citation |url=http://www.cablelabs.com/specifications/PKT-SP-CODEC-MEDIA-I07-090702.pdf |page=87 |title=PacketCable 2.0 - Codec and Media Specification - PKT-SP-CODEC-MEDIA-I07-090702 |year=2009 |access-date=2011-06-23}}</ref><ref name="voiceage-vmrwb">{{citation|url=http://www.voiceage.com/vmrwb.php |title=VoiceAge website: VMR-WB — Source-controlled Variable Bit Rate Wideband Compression (archived) |date=2008-04-19 |access-date=2011-06-23 |url-status=dead |archive-url=https://web.archive.org/web/20080419094934/http://www.voiceage.com/vmrwb.php |archive-date=April 19, 2008 }}</ref> Algorithmic delay is 33.75ms.

VMR-WB can be also used in [[3GPP2]] container file format - [[3GP|3G2]].

VMR-WB was designed by [[Nokia]] and VoiceAge. It is based on AMR-WB.<ref name="voiceage-vmrwb" />

== References ==
{{reflist}}

== External links ==
* [https://web.archive.org/web/20041102200753/http://www.3gpp2.org/Public_html/Specs/C.S0052-0_v1.0_040617.pdf 3GPP2 specification]
* {{IETF RFC|4424|link=no}} - Real-Time Transport Protocol (RTP) Payload Format for the Variable-Rate Multimode Wideband (VMR-WB) Extension Audio Codec
* {{IETF RFC|4348|link=no}} - Real-Time Transport Protocol (RTP) Payload Format for the Variable-Rate Multimode Wideband (VMR-WB) Audio Codec
* [https://web.archive.org/web/20080419094934/http://www.voiceage.com/vmrwb.php VoiceAge website: VMR-WB — Source-controlled Variable Bit Rate Wideband Compression (archived)]
* [http://www.voiceage.com/vmrwb.php VoiceAge website]

{{Compression formats}}

[[Category:Speech codecs]]


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